Dr. Jasper de Goeij

Dr. Jasper de Goeij

Dr. Jasper de GoeijPorifarma B.V.
Poelbos 3
6718 HT Ede
The Netherlands

Tel: +31 (0) 6 52471433
E-mail: jdegoeij@porifarma.com

Education and Degrees:
2001 M.Sc. Biology, Wageningen University, Netherlands.
2008 Ph.D. Biology; University of Groningen

Recent publications relevant to Curacao:

General research interests:
Biogeochemical cycling on coral reefs; Organic and inorganic matter dynamics; Coral reef cavities; Sponge nutrition, physiology (cell cycling), and ecology; Marine Biotechnology; Aquaculture.

Research interests on Curacao:
The past five years I have been investigating the role of coral cavities (the coral reef’s framework) in the nutrient cycling (organic and inorganic) of the tropical coral reef ecosystem; especially the important role of encrusting sponges, inhabiting the cavities.

I started my “CARMABI career” as an MSc student from the Wageningen University and the University of Amsterdam in 1999, under supervision of Sander Scheffers, with a project on the dimension of coral cavities and the bacterial dynamics within those cavities. My PhD was a continuation on this topic, but with a scope towards the dissolved organic matter (DOM) cycling within the system.

Coral cavities are major sinks of dissolved organic carbon (DOC) and the influx of DOC into coral cavities is so high, it is in the same order of magnitude as the gross primary production of an entire reef!

By measuring organic and inorganic fluxes of the four surface dominating communities of coral cavities (sediment, sponge, calcareous algae, and bare substrate; ~88% of the total surface area), we were able to construct a complete energy budget for the coral cavities, which comprise up to two-thirds of the volume of a reef. Coral reef framework cavities are the major habitat in respiration processes in the coral reef ecosystem, accounting for 27-68% of the gross community respiration of an entire reef ecosystem.

Sponges play, by far, a key role in the nutrient cycling within the cavities. Most of their carbon intake (>90%) consists of DOC. Sponges capture locally produced DOM and convert it into particles, facilitating the retention of nutrients within the ecosystem, like a ‘cryptic carbon shunt’. The conversion of DOM into particles as a mechanism for energy transfer in marine systems has been described in earlier studies as the so-called ‘microbial-loop’. In coral cavities, not the bacterioplankton, but the sponge community functions as a ‘sponge loop’.

Through 13C-tracer experiments and sponge fatty acid analysis, we found that both sponge cells and bacteria are able to take up and assimilate DOM. We also found a major discrepancy in the extreme high carbon intake (35-40% body C d-1) and the low net increase of biomass by the sponge (close to zero).
In vivo cell kinetics of the marine sponge Halisarca caerulea showed extremely high proliferation activity, short duration of the cell cycle, and massive cell shedding. To our knowledge, such fast cell kinetics and turnover have not been observed previously in any other multi-cellular organism. Functional morphology of the sponge corresponds well with its remarkable cellular kinetics and shows a striking resemblance with the human gastrointestinal tract.

Coral cavity sponges, like Halisarca caerulea inhabit very low nutrient tropical waters, forcing these organisms to filter large volumes of water and to capture the few nutrients very efficiently. Under these oligotrophic conditions, a high cell turnover can be considered as a very useful strategy, preventing permanent damage by environmental stress. Since sponges are recognized as important potential sources for new drugs, anti-biotics and biomaterials, these data may be helpful to improve the culturing of sponges.

I hope to continue my work on the physiology and cell kinetics of sponges in the near future and I’m looking forward to continue working at CARMABI for a long time!